1. Field of the Invention
This invention relates to a camera having a pop-up type flash device which is arranged to move from a stowed position to a usable position.
2. Description of the Related Art
It is desirous to have a flash device of a high guide number for high-quality flash photography. To meet this requirement, flash devices of varied types having high guide numbers have been proposed. For forming a flash device of a high guide number, it is known to increase the capacity of a capacitor, to use a larger xenon discharge lamp, to increase the size of the lens panel disposed in front of the xenon discharge lamp and so on. Further, for making the guide number larger, it has been practiced to do zooming by moving back and forth a unit consisting of the xenon discharge lamp and a reflection shade in such a way as to use the unit in a position most efficient for a photo-taking lens in use.
However, the conventional method of forming the high-guide-number flash device by increasing the size of the capacitor, that of the xenon discharge lamp or that of the lens panel hinders a reduction in size of a camera of the kind having a built-in flash device or even a camera arranged to use an external flash device.
In the case of the camera having a built-in flash device, in particular, an increase in capacity of the capacitor causes an increase in size of the camera as a whole. In addition to the increase in size, the increased capacity requires a longer period of time in charging the capacitor and is thus very disadvantageous for quick flashing.
Further, an increase in size of the xenon discharge lamp results in an increase in the size of a part located above a pentagonal prism only in the film feeding direction. It is thus impossible to efficiently increase the guide number. Besides, the larger xenon discharge lamp makes designing work difficult.
The guide number can be increased by widening the lens panel disposed in front of the xenon discharge lamp. However, the larger lens panel presents a problem with respect to stowing arrangement for stowing the lens panel when the flash photography is not required. The use of a larger lens panel, therefore, has not been proposed for the pop-up type flash device.
Further, the conventional flash device which is of the kind having a variable illuminating angle and is shiftable between a usable (or service) position and a stowed position is arranged, as disclosed in Japanese Laid-Open Patent Application No. SHO 63-195638, etc., to move to the stowed position or the usable position and to change the illuminating angle by means of a continuously extended cam arrangement. Further, the series of these actions are arranged to be carried out by using a special motor as a drive source.
In the case of the example of the conventional arrangement described above, a flash-device stowing cam is arranged as an extension of an illuminating-angle varying cam. This arrangement increases a cam operating stroke and thus necessitates a stowing space to include room for the increased cam stroke. It is thus a drawback of the arrangement that the size of the flash device increases even in its stowed state. Another drawback lies in that the variable degree of the illuminating angle is insufficient as compared with the length of the cam operating stroke since the whole cam operating stroke cannot be fully used as an illuminating-angle varying stroke.
The flash device might be broken when it is touched by the user while the device is in the usable position. This problem is solvable by arranging a cover in such dimensions that can cover the flash device in the usable position. That arrangement, however, results in an increase in size of the camera. It is natural in the sense of the user that the user might wish to push the flash device by hand back to the stowed position after the flash device has moved to the usable position. Since the camera is to be taken up by hand and operated by a human being, it is important for the camera to be a tool which is user friendly.